Biomaterial Database

A fluorometric assay using 4-methylumbelliferyl alpha-L-iduronide for the estimation of alpha-L-iduronidase activity and the detection of Hurler and Scheie syndromes. 1979

J J Hopwood, and V Muller, and A Smithson, and N Baggett

Incubation of 4-methylumbelliferyl alpha-L-iduronide with whole cell homogenates prepared from cultured skin fibroblasts and amniotic cells, and peripheral blood leukocytes gave 4-methylumbelliferone which was easily measured fluorometrically. This reaction, presumably due to the action of alpha-L-iduronidase, has a maximum hydrolytic activity at pH 3.25. The apparent KM value of alpha-L-iduronidase in leukocyte whole cell homogenates for this substrate was 179 mumol/l compared to 353, 41 and 166 mumol/l for other alpha-L-iduronidase substrates phenyl alpha-L-iduronide, iduronosyl anhydrol[1-3H]mannitol 6-sulfate and iduronosyl anhydro[1-3H]mannitol respectively; the corresponding Vmax values were 617, 394, 158 and 10 pmol/min/mg protein respectively. Incubation of the 4-methylumbelliferyl alpha-L-iduronide with whole cell homogenates prepared from cultured skin fibroblasts and leukocytes from a Hurler patient gave 4-methylumbelliferone at a rate more than 20 times less than found for control normal preparations. 4-Methylumbelliferyl alpha-L-iduronide is a sensitive, convenient and superior substrate to phenyl alpha-L-iduronide for the assay of alpha-L-iduronidase activity, but is not a suitable replacement for the radiolabelled substrate iduronosyl anhydro[1-3H]mannitol 6-sulfate.

UI	MeSH Term	Description	Entries
D007068	Iduronidase	An enzyme that hydrolyzes iduronosidic linkages in desulfated dermatan. Deficiency of this enzyme produces Hurler's syndrome. EC 3.2.1.76.	alpha-L-Idosiduronase,alpha-L-Iduronidase,alpha L Idosiduronase,alpha L Iduronidase
D007962	Leukocytes	White blood cells. These include granular leukocytes (BASOPHILS; EOSINOPHILS; and NEUTROPHILS) as well as non-granular leukocytes (LYMPHOCYTES and MONOCYTES).	Blood Cells, White,Blood Corpuscles, White,White Blood Cells,White Blood Corpuscles,Blood Cell, White,Blood Corpuscle, White,Corpuscle, White Blood,Corpuscles, White Blood,Leukocyte,White Blood Cell,White Blood Corpuscle
D008059	Mucopolysaccharidosis I	Systemic lysosomal storage disease caused by a deficiency of alpha-L-iduronidase (IDURONIDASE) and characterized by progressive physical deterioration with urinary excretion of DERMATAN SULFATE and HEPARAN SULFATE. There are three recognized phenotypes representing a spectrum of clinical severity from severe to mild: Hurler syndrome, Hurler-Scheie syndrome and Scheie syndrome (formerly mucopolysaccharidosis V). Symptoms may include DWARFISM; hepatosplenomegaly; thick, coarse facial features with low nasal bridge; corneal clouding; cardiac complications; and noisy breathing.	Hurler's Syndrome,Hurler-Scheie Syndrome,Lipochondrodystrophy,Mucopolysaccharidosis V,Pfaundler-Hurler Syndrome,Scheie's Syndrome,Gargoylism,Gargoylism, Hurler Syndrome,Hurler Disease,Hurler Syndrome,Hurler's Disease,Mucopolysaccharidosis 1,Mucopolysaccharidosis 5,Mucopolysaccharidosis I-S,Mucopolysaccharidosis Type I,Mucopolysaccharidosis Type Ih,Mucopolysaccharidosis Type Ih S,Mucopolysaccharidosis Type Is,Scheie Syndrome,alpha-L-Iduronidase Deficiency,Disease, Hurler's,Gargoylisms,Hurler Scheie Syndrome,Hurler Syndrome Gargoylism,Lipochondrodystrophies,Mucopolysaccharidosis I S,Mucopolysaccharidosis Is,Mucopolysaccharidosis Type Ihs,Syndrome, Hurler's,Syndrome, Scheie's,Type Ih, Mucopolysaccharidosis,Type Ihs, Mucopolysaccharidosis,alpha L Iduronidase Deficiency,alpha-L-Iduronidase Deficiencies
D009083	Mucopolysaccharidoses	Group of lysosomal storage diseases each caused by an inherited deficiency of an enzyme involved in the degradation of glycosaminoglycans (mucopolysaccharides). The diseases are progressive and often display a wide spectrum of clinical severity within one enzyme deficiency.	Mucopolysaccharidosis
D005470	Fluorometry	An analytical method for detecting and measuring FLUORESCENCE in compounds or targets such as cells, proteins, or nucleotides, or targets previously labeled with FLUORESCENCE AGENTS.	Fluorimetry,Fluorometric Analysis,Analysis, Fluorometric
D006026	Glycoside Hydrolases	Any member of the class of enzymes that catalyze the cleavage of the glycosidic linkage of glycosides and the addition of water to the resulting molecules.	Endoglycosidase,Exoglycosidase,Glycohydrolase,Glycosidase,Glycosidases,Glycoside Hydrolase,Endoglycosidases,Exoglycosidases,Glycohydrolases,Hydrolase, Glycoside,Hydrolases, Glycoside
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000653	Amniotic Fluid	A clear, yellowish liquid that envelopes the FETUS inside the sac of AMNION. In the first trimester, it is likely a transudate of maternal or fetal plasma. In the second trimester, amniotic fluid derives primarily from fetal lung and kidney. Cells or substances in this fluid can be removed for prenatal diagnostic tests (AMNIOCENTESIS).	Amniotic Fluid Index,Amniotic Fluid Indices,Amniotic Fluids,Fluid Index, Amniotic,Fluid Indices, Amniotic,Fluid, Amniotic,Fluids, Amniotic,Index, Amniotic Fluid,Indices, Amniotic Fluid
D012867	Skin	The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.
D014468	Umbelliferones	7-Hydroxycoumarins. Substances present in many plants, especially umbelliferae. Umbelliferones are used in sunscreen preparations and may be mutagenic. Their derivatives are used in liver therapy, as reagents, plant growth factors, sunscreens, insecticides, parasiticides, choleretics, spasmolytics, etc.	7-Hydroxycoumarins,Hydrangin,Skimmetin,7 Hydroxycoumarins